Electric circuit breaker



Sept. 30, 1952 E LANGE 2,612,576

ELECTRIC CIRCUIT BREAKER Filed Feb. 24, 1948 5 46 11k as I vmim' 'FlG.4-

Patented Sept. 30, 1952 Emil Lange, Paris, France Application February 24, 1948, Serial No. 10,339 v In France June 12, 1946 This invention relates to electric circuit breakers in which the extinguishing of the arc is efiected in an extinguishing chamber by one or more currents of quenching medium produced by the arc itself.

One object of the invention is to provide an improvedcircuit breaker.

:A further object is to achieve efficient extinction of the are by causing the quenching medium to now throughone or two hollow contacts.

' A circuit breaker of thekind'in which the arc is extinguished by one or more currents of quenching medium produced by the arc itself is provided according to the invention with an extinguishing chamber which comprises an arc chamber surrounded by a counter pressure chamber, these latter two chambers coming into communication with each other by one or more apertures permitting an equilisation of the pressure in the arc chamber and thecounter-pressure chamber by currents/of quenching medium which pass through the are, and the counter-pressure chamber enlarges when the pressure attains a pre-determined value.

- Further objects and features of the invention appear'from the following description read in conjunction with the accompanying drawing.

In the accompanying drawings three forms of circuit breaker according tovthe invention are illustrated by way of example,

I Figure 1 being a sectional elevation of one circuitbreaker,

Figure-2 a sectional elevation of a second circuit breaker,

Figure 3 a cross sectional view on the line AA ofFigure 2, and; v I i Figure 4 a sectional elevation of a third circuit breaker.

'- ;Referring to Figure l of the said drawings; the circuit breakercomprises an arc chamber l surrounded by a counter-pressure chamber 2. A fixed contact 3 serves to make contact with the moving contact bar l. This fixed contact 3 is piercedso that communication is established be* tween the arc chamber l and the counter-pressure chamber 2, thelatter being closed by a mov: ablecover 5 which normally'rests on a support ring 1. '-A spring 6, which is under constraint while at' rest, is arranged above the movable cover 5 and does notpermit the latter to move until the pressure'in the counter-pressure chamher i 2' attains a predetermined value. Apertures 8 formed in the cover'5 establish communications with the space 9 above the cover 5. The quenching' medium may be a liquid (for example oil),

8 Claims.- (Cl. 200-450) gaseous (for example an inert gas) or'solid' (in ert powder). It fills the counter-pressure chamber 2 and part of the space 9. v

. The circuit breaker functions as" follows.

assuming the quenching medium to be a liquid.

Suppose that the movable contact bar 4 is {connected to one pole of a source of current and that the fixed contact 3 is connected to'the other'pole so that the current flows through one contact'to the other. When the contacts 3 and 4 areseparated to break the current an arc is produced between them. The liquid in contact with the arc is vaporised and in consequence the arc is surrounded by a mass of gas at very high'temperature which produces a sudden increase of pressure in the arc chamber I. This increase iii-pressure is transmitted immediately to theco'unterpressure chamber '2 by the aperture 3a inthe pierced contact 3. When the arc is producedby the breaking of a small current the increase in pressure in the arc chamber l and in the counter-pressure chamber 2 is relatively "small and is not capable of overcoming the pressure exerted by the spring 6 on the movable cover 5, so that the movable coverremains in the position shown in the drawing. A little fluid 'underpressure passes through the apertures 8 into the space 9. In consequence of this dispersal of part'oi the fluid contained in the counter-pressure chamber 2 the pressure in thischamber is reducedg The are continuing to burn in the arc chamber l continues to vaporise the. liquid so, that thepressure in the arc chamber continues to increase. j'In consequenceof the'reduction of pressure inthe counter-pressure chamber 2 there is established through the pierced contact 3 in which thebase of the arc is burning a difference of pressure so that the quenching medium continues to leave the arc chamber l and enter the counter-pressure chamber 2. Underthe action of the counter-.- pressure of the quenching medium contained in the counter-pressure chamber 2 the .arc is com.- prised and this movement of thequenching medium has a particularly effective action in extinguishing the arc. I j;

When the arc is extinguished the increase in pressure immediately ceases. The remainder of the gases producing the pressure leaves the arc chamber I and enters the counter pressure chamber 2. It is only when the gases have en;-,- tered the space 9 by passing throughthe apertures 8 that the quenching medium contained in the chambers l and 2 is no longer under pressure, which results in aiavourable extinguishingfacti'on.- 3

When a large current is broken the increase in pressure is transmitted in a similar way from the arc chamber I to the counter-pressure chamber 2. In consequence of the great increase in pressure the force exerted on the movable cover is sufficient to overcome the force of the spring 6 in spite of the apertures 8. The movable cover 5 is therefore forced upwards. In consequence of this movement the volume of the counterpressure chamber 2 is increased and the danger of an excessive pressure rise is obviated. The are burning in the pierced contact 3 is blown out in an eflicient manner and is quenched by the current of quenching medium and compressed by the counter-pressure of the quenching'medium contained in the chamber 2. Because of the pressure exerted by the spring 6 on the movable cover 5 the counter-pressure adjusts itself according to the movement of quenching medium produced by the arc depending upon the strength of the broken current so that there-is always produced awcurrent of quenching medium favourable for extinguishing the arc.

The'blowing out of the arc in the pierced contact 3 under the action of the counter-pressure of the quenching'medium in the chamber 2 isof great importance in extinguishing the arc. This counter-pressure produces an accumulation of pressure in the quenching medium in the arc chamber l as well as in the counter-pressure chamber '2. Equilisation of the pressure between the arc chamber and the counter-pressure chamber does not take place suddenly by a rapid change from maximumto minimum pressure; but

there is maintained'a current of some duration between thelimits of a predetermined range of pressure. An increase of pressure takes place while the arc continues to burn in spite of the expulsion of quenching medium.

Referring to Figure 2 of the drawings, the extinguishing chamber comprises'an arc chamber lli.surrounded by a counter-pressure chamber 11. A fixed contact [5 provided with anaperture I5ais arranged in the chamber [6 and its complementary contact is a movable contact bar l8. This bar I8 is bored for part of its .lengtlrand is provided with slits I 9 which establish communication between the arc chamber 16- andthe counter-pressure chamber .l'i when the contact bar [8 is separated from the fixed contact IS. The lengthlof the tubular part 29 at theend of the bar I 8 is. such relatively to the point where the slits I9 commence that the various pressure compartments 2| are closed, in spite of the slits l9, by the extremity of the bar l8. in such a way that the quenching medium is constrained toupassout. throughthe extremity of the bar IS.

The are chamber [6 is closed at its. upper end by a tube 22 in which are formed apertures 23. The'counter-pressure. chamber I1 is closed by a movable lid 24 in which are formed apertures 2'! andwhich, inthe position shown, is urged against aring 26.by a compression spring 25. Additional quenching medium is. accommodated in the. space 28 above the movable lid 24..

The circuit breaker functions asfollowswhen filled. with a liquid quenching medium. When the contacts [5 and- I8 are separated there. is

produced in the arc chamber l6 an are which lengthens and causes an increase of pressure. The arc chamber I 6 and the counter-pressure chamber I! are now-incommunication through the pierced contact l5 and by the hollowpart of the contact bar 18 through the slits I9 and the apertures 23 so that the increase of pressure is partially transmitted to the counter-pressure chamber. In the case of an are produced by the breaking of a small current the increase in pressure is relatively small. This increase in pressure is not capable of overcoming the force exerted by the spring 25 on the movable lid 24. Part of the quenching medium contained in the counter-pressure chamber is expelled through the apertures 21 under the action of the small increase in pressure. These apertures are so dimensioned that an increase in pressure is maintained in the counter-pressure chamber H in spite of the expulsion of part of the quenching medium. The contact bar l8 continuing to rise, the. arc continues to lengthen and produce further. increases in pressure in the arc chamber IS. The slits l9 pass before the apertures 23, maintaining communication with the counter-pressure chamber H, while the pierced contact l5 maintains. communication attheother end. The. are burns with one of its striking points inthe pierced contact. l5. and; the. other striking point in. the hollow bar I8. In consequence of the fall in pressure in. the"counterpressure chamber l1 thereJis established through the pierced contacts [5 and IS? a pressure which gives rise-to a-double current-of'quenching medium directed towards the two striking points of the-arc. Each ofthese'striking points is. thus subjected to theaction of. a current ofquenching medium suchthat the arc is readily extinguished; The extremity 29'of. the contact bar: l8: has a length such that. it always closes' those cham bers 21 which it traverses-so that thecurrent of quenching; medium is constrained to pass through the extremityof the contact barand blow out the are which burnsat that point;

When; a large: current: is broken. the force or the-spring, 25 acting orrthemovable lid 2l=is overcome and? the volume. 01" the counter-pressure chamber flzis increased, preventing excess pressure .inthat chamber. The counter-pressure of the quenching medium contained in the-counter pressure chamber exercises a similar action to that whichhasbeendescribed above'. The two currents. of 'quen'ching'medium ensure an eflicient extinction of the-arc;

Referring to Figure: 4- of' the accompanying drawings, the circuit; breaker comprises an arc chamberv 48. surrounded by a counter-pressure chamber 49, a fixed contact 50, a contact bar 5|, a movable cover 33; a spring 52, apertures 53in the movable cover and a space 54 above the movable cover. The are: chamber 48 is-secured by means of a supporting ring on the base 31 of. the. apparatus. It is: extended upwardly into a tubular part 32 in which may move the contact bar 51. On the extension otthe'said chamber is a shoulder. whiclrservs' to locate the cover 33. On the-upper: part is-secured a ring 34 against which the spring 52- abuts: The external wall. 55 of the counter-pressure chamber is-sealed by'mea-nsof a sealing-joint 39' in a flange secured by thev supporting ring 30. At the top; of; thespace- 54 is arranged a cover 31 with a sealing-joint. 3B; The. interiorsof'the arcchamber communicates atits lower and through apertures and at its upper'endthro'ugh apertures 56 with'the counter-pressure chamber .49. A fixture 4.0 isarranged inside thearc chamber 48, and is divided throughout its height by partitions 41 into a series-of compartments 42 each partition having an aperture through which passes the; contact bar; 51. 'Ihiscontact bar thelowerpart of whichfis hol1ow,fis provided withlongitudinal slits 45 smmmtne slits IQ in'flFiguref2. Theupper surfaces 46'-and l1 of the apertures 39 and 56 and'also the lowerfaces of the partitions and the.lowerparts--of the apertures 53 are inclined so as to prevent the formation of stationary bubbles and pockets of gas; The are chamber 48' serves not only as an arc chamber but also to support the moving parts of the circuit breaker and so distributes to the "different parts the mechanical forces which arise during the functioning of thfapp a Theapparatusfunctions as follows. Suppose that the contact bar '5! is in the position 5m in which it is inv contact with the annular contact 50 sothat the current passes from the baseplate 3| to the contact bar 5|. If the latter is displaced upwardly an arc is produced between thejc'ontact bar 5| and the annular contact 50. This are gives rise to a sudden increase in pressurein. the quenching medium, forexamplean extinguishing liquid, which fills the apparatus Q's far as the surface 46. This increase in press'ur'e' is' transmitted through theapertures 39 and ,56, and the slits45 in the bar 5i to the counterpressurechamber 49. Under the action of 'this sudden increase in pressurelthe cover 33 is raised against'the action of the spring 52. Owing to the arrangement of the apertures 39 and 56 and, of' the compartments 42 and the apertures 53 any gas which may be generated cannot form into stationary pockets. ,The pressure which is established almost immediately results in avery rapid flowing of quenching medium on to the arc which as a result is extinguished immediately. The mechanical forces which arise during the quenching of the arc, the effect of the rapid rise in pressure, are transmitted by means of the movable cover33 and the spring 52 to the arc chamber itself which absorbs these forces. The movable cover 33 assists: in dissipating the momentary forces. The construction of-theii'arc chamber in accordance with the invention ensures a. great solidity and certainty inaction so as torinfluence favourablya quenching of the arc..

In all the described cir nit-breakers, the

counter-pressure produces an accumulation of pressure in the quenching-medium in the arc chamber so that the arc is compressed, whereas the difference between the pressures in the arc chamber and the counter p'ressure chamber and the rate of flow between these chambers is as great as if no counter-pressure were exerted. The arc, being compressed, is more rapidly extin guished.

What I claim and desire to secure by Letters Patent is:

1. An electric circuit breaker of the kind in which the arc is extinguished by at least one current of quenching medium produced by the arc itself, comprising an arc chamber, a fixed perforated electric contact in a wall of said arc chamber, a movable electric contact having one end capable of moving within said are chamber into and out of contact with said fixed contact, a counter-pressure chamber surrounding said are chamber, a quenching medium at least partially filling said are chamber and said counter-pressure chamber, and at least one of the members which form said counter-pressure chamber being displaceable by excess pressure in said quenching medium in said arc chamber and said counter-pressure chamber whereby under excess @BIQBVB ,6 pressure the internal volume of said counterpressure chamber is increased, the arrangement being such that the counter-pressure" of the quenching" medium in the" counter-pressure chamberproduces a corresponding accumulation of pressure in the quenching medium in the arc chamber and the arc is compressed.

2. An electric circuit breakerof'thekind in which the arc is extinguished by at least one current of quenchingmedium produced by the arc itself, comprising an arc chamber, a fixed perforated electric contact in a wall of said are chamber, a movable electric contact having one end capable of moving within said arc' chamber into and out of contact with said fixed contact. a counter-pressure chamber surrounding said are chamber,- a quenching medium at least partially filling said are chamber and said counter-pressure chamber, and at least one Of the members which form said counterepressure chamber being spring-loaded and slidably displaceable by excess pressure in said quenching medium in said are chamber and said counter-pressure chamber whereby under excess pressure the internal volume of said counter-pressure chamber is in creased, the arrangement-being such that the counter-pressure of the quenching medium in the counter-pressure chamber produces a corresponding accumulation of pressure in the quenching medium in the arc chamber and the arc is compressed. I

'3. An electric circuit breaker ofthe kind in which the arc is extinguished byat least one current of quenching medium produced by the arc itself, comprising an arc chamber, a fixed perforated electric contact in a Wall of said are chainber, a movable electric contact having oneend capable ,of moving within said are chamber into and out of contact with said fixed contact', a counter-pressure chamber surrounding said are chamber, a quenching medium at least partially filling said arc chamber and said counter-pres:- sure chamber, and at least one of the members which form said counter-pressure chamber being apertured and spring-loaded and slidably displaceable by excess pressure in said quenching medium in said arc chamber and said counter pressure chamber whereby under excess pressure the internal volumeof vsaid counter-pressure chamber is increased, th arrangement "being such that the counter-pressure of the quenching medium in the counter-pressure chamber produces a corresponding accumulation of pressure in the quenching medium in ,the arc chamber and the arc is compressed.

4. An electric circuit breaker of the kind in which the arc is extinguished by at least one current of quenching medium produced by the arc itself, comprising an arc chamber, a fixed perforated electric contact in a wall of said are cham-- ber, a movable electric contact having one end capable of moving within said are chamber into and out of contact with said fixed contact, a counter-pressure chamber surrounding said arc chamber, a quenching medium at least partially filling said are chamber and said counter-pressure chamber, one of the members forming said counter-pressure chamber being apertured and spring-loaded and slidably displaceable by excess pressure in said quenching medium in said are chamber and said counter-pressure chamber whereby under excess pressure the internal volume of said counter-pressure chamber is increased, and said movable contact being at its contact end tubular and apertured and thereby acreage aflordingpassage. for said quenching m dium from saidarc chamber. to said counter-pressure chamber,, thearrangement being such that the counter-pressure of the quenching medium in the: counter pressure chamber produces a corresponding accumulation of pressure in, the quenching medium, in the arc chamber and the arcis compressed.

5. A circuit breaker-as claimed in claim 4, wherein; said counter-pressure chamber and, said spring-loaded slidably displaceable member are mounted on said arcchamber and said are cham: ber. absorbs the mechanical forces acting within therdevice during functioning,

61 An electric circuit breaker of the kind, in which. the. arc isextinguished by at least onecurrent:o quenching medium produced by the arc itself, comprising an arc chamber, a fixed perforated electric contact in a wall of said arcchamber,.a. movable electric contact having one end capable of moving within saidarc chamber into andout of contact with. said fixed contact, a counter-pressurev chamber surrounding said are chamber, a quenching medium at least partially filling said, are chamber and said counter-pressure chamber, one of the members forming said counter-pressure chamber being apertured and spring-loaded and slidably displaceable by excess pressure in said quenching medium in said are chamber and said counter-pressure chamber whereby under excess pressure the internal volume of said counter-pressure chamber is increased, and, said movable contact being at its contact end tubular and apertured and thereby afiording. passage. for said, quenching medium from said are chamber to said counter-pressure chamber, and the upper part of said are chamber being tubular, and a, compression spring externally mounteclon said tubular upper part of said arc chamber and engaging said slidably displaceable-member, saidslidably displaceable member being slidable on. said tubular upper part of said are chamber, the arrangement, being such that the, counter-pressure of the quenching medium inthe-counter-pressure chamber produces a corresponding accumulation of pressure in the quenching mediurnin the arc chamber and the arc is, compressed.

7'. ,An electric circuit breaker of the kind in which the arc is extinguished by at least one current of quenching medium produced by the arc itself, comprising an arc chamber, a fixed perforated electric, contact in a Wall of said arc chamber, amovable electric contact having one end capable of moving within said arc chamber into. and out. ofcontact; withsaid fixed contact. a: counterrpressure; chamber surrounding saidarc chamber, arquenching medium atv least partially fillingsaidarc; chamber and said counter-pressure chamber,. one,- or the members formingf said counter-pressure. chamber. being aperturedI and spring-loadedandslidably displaceable by, ex,- cess pressure in said. quenching. medium in said arc chamber and said counter-pressure chamber wherebyunder-excess-pressure the internal volume. of; said counter-pressure chamber is, iii-'- creased; and, said movable contact being at. its contact end tubular and apertured and thereby affording passage for said quenching. medium fromsaidarachamber to said counter-pressure chamberand the-upper part. of said arc chamber being tubular, and a compression. spring externally mounted on said tubular upper part or said arcv chamber and engagingsaidslidably displace: able member, said slidably displaceable member being slidable on said. tubular upperpart-otsaid arc chamber,, and said, are chamber being internally compartmented, and the compartments being successively closed during circuit-breaking by. said tubular end i said movable contact whereby quenching medium is caused to pass through the arc, in escaping through said tubular end, the arrangement being such that the counter-pressure or the, quenching medium in the counter-pressure chamber produces a corresponding. accumulationoi pressure in thequenching medium in. the arc chamber and" the arc is compressed.

8., A circuitbreaker as claimed inv claim 7; having all downwardly facingsurfaces in said arc chamber andsaidspring-loaded member inclined to the horizontal and thus leading away any gas bubbles produced during. functioning,

EMIL LANGE;

REFERENCES CITED The-following references are of. record inthe file of this patent:

UNITED STATES PATENTS 

